gdb/testsuite/gdb.base/fork-running-state.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2015-2020 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include <unistd.h>
  19 #include <stdio.h>
  20 #include <sys/types.h>
  21 #include <sys/wait.h>
  22 #include <errno.h>
  23
  24 int save_parent;
  25
  26 /* Variable set by GDB.  If true, then a fork child (or parent) exits
  27    if its parent (or child) exits.  Otherwise the process waits
  28    forever until either GDB or the alarm kills it.  */
  29 volatile int exit_if_relative_exits = 0;
  30
  31 /* The fork child.  Just runs forever.  */
  32
  33 static int
  34 fork_child (void)
  35 {
  36   /* Don't run forever.  */
  37   alarm (180);
  38
  39   while (1)
  40     {
  41       if (exit_if_relative_exits)
  42         {
  43           sleep (1);
  44
  45           /* Exit if GDB kills the parent.  */
  46           if (getppid () != save_parent)
  47             break;
  48           if (kill (getppid (), 0) != 0)
  49             break;
  50         }
  51       else
  52         pause ();
  53     }
  54
  55   return 0;
  56 }
  57
  58 /* The fork parent.  Just runs forever.  */
  59
  60 static int
  61 fork_parent (void)
  62 {
  63   /* Don't run forever.  */
  64   alarm (180);
  65
  66   while (1)
  67     {
  68       if (exit_if_relative_exits)
  69         {
  70           int res = wait (NULL);
  71           if (res == -1 && errno == EINTR)
  72             continue;
  73           else if (res == -1)
  74             {
  75               perror ("wait");
  76               return 1;
  77             }
  78           else
  79             return 0;
  80         }
  81       else
  82         pause ();
  83     }
  84
  85   return 0;
  86 }
  87
  88 int
  89 main (void)
  90 {
  91   pid_t pid;
  92
  93   save_parent = getpid ();
  94
  95   /* The parent and child should basically run forever without
  96      tripping on any debug event.  We want to check that GDB updates
  97      the parent and child running states correctly right after the
  98      fork.  */
  99   pid = fork ();
 100   if (pid > 0)
 101     return fork_parent ();
 102   else if (pid == 0)
 103     return fork_child ();
 104   else
 105     {
 106       perror ("fork");
 107       return 1;
 108     }
 109 }